<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        *{
            background: black;
        }
        /* 简陋版 */
        .d1,.d2{
            width: 200px;
            height: 200px;
            background: red;
            border-radius: 50%;
        }
        .d2{
            height: 100px;
            background: white;
            border-radius: 0 0 100px 100px;
            margin-top: -100px;
        }

        .d3{
            width: 30px;
            height: 110px;
            background: white;
            margin: -3px 0px 0px 85px;
        }

        /* 优化版 */
        .d4{
            width: 200px;
            height: 200px;
            background: white;
            border-radius: 50%;
            box-shadow: 0px 100px 0px 0px red inset;
        }
        .d5{
            width: 30px;
            height: 110px;
            background: white;
            margin: -3px 0px 0px 85px;

        }

    </style>
</head>
<body>
<div class="d1"></div>
<div class="d2"></div>
<div class="d3"></div>


<div class="d4"></div>
<div class="d5"></div>
</body>
</html>